Trials involving 30,000 people in the US for the vaccine being developed by the University of Oxford and AstraZeneca remain on hold while the US Food and Drug Administration conducts its own investigation into a reported side effect in a UK patient.
The illness in a volunteer temporarily brought a halt to all the trials of the vaccine worldwide – which also involve thousands of people in the UK, South Africa and Brazil.
Oxford said at the time that it was “expected” that in large-scale trials some people would become ill, but after an investigation into whether the illness was linked to the vaccine it was deemed safe to continue. The vaccine is seen as a likely contender to be first to market.
Meanwhile, Johnson and Johnson has become the fourth pharmaceutical company to begin the final large-scale trials of a Covid-19 vaccine.
The company said the trials will involve 60,000 people, across the Americas and in South Africa.